The present invention relates to substrates, particularly for use in absorbent articles, comprising flocked fibers of superabsorbent polymer.
The use of superabsorbent polymers in absorbent articles, such as sanitary napkins, pantiliners, diapers, and incontinence pads is known. Superabsorbent polymers enhance the liquid management properties of absorbent articles, such as capacity and retention of fluids. They are added to the components of absorbent articles in the form of particles or fibers, but most often in the form of particles. Most commercially available processing equipment is designed to handle superabsorbent polymer particles rather than fibers, since fibers are more difficult to disperse than particles and tend to collapse.
Superabsorbent polymers are typically found in the absorbent core of an absorbent article, where they are easily incorporated. However, it would be desirable to be able to employ superabsorbent polymers in a convenient manner in and on other kinds of substrates, such as other nonwoven materials, polymer films, apertured films, netting, woven fabrics, foams, reticulated films, and the like.
Flocking is a technique by which fibers are fixed in a vertical position on a substrate, and is primarily used in the fabric industry. However, EP 0 737 462 A1 discloses a laminated material to cover the outside of an absorbent product, characterized in that at least one portion of the surface of the laminated material bears a layer of fibers applied by flocking. The flocked fibers are thereby located on the external surface of the absorbent product in order to give the absorbent product improved tactile properties over products that employ plastic films against the skin. EP 0 737 462 A1 discloses that the external surface to which the flocked fibers may be applied may be a perforated cover. The cover may be perforated before or after the flocking is applied, but is preferably perforated before flocking.
Applicant has discovered that fibers of superabsorbent polymer may be advantageously adhered to a variety of substrates by flocking. According to the invention, when flocked fibers of superabsorbent polymer are applied to a substrate, they stand in an upright, vertical manner on the surface. Such an orientation allows the flocked fibers of superabsorbent polymer to absorb an increased amount of fluid compared with unflocked fibers of superabsorbent polymer, i.e., fibers compressed horizontally. This in turn makes substrates comprising flocked fibers of superabsorbent polymer particularly attractive for use in absorbent articles of all types.
Applicant has also discovered that flocked fibers of superabsorbent polymer may advantageously be applied to the surface of an apertured film. In particular, an apertured film comprising flocked fibers of superabsorbent polymer on its underside surface, and additionally on the outer surfaces of the aperture sidewalls, provides an improved cover or other component of an absorbent article. Materials and manufacturing technology have enabled the development of nonwoven fabric and polymer apertured films that mimic the feel of woven fabric quite well. And although many variations of apertured films exist in the art, improved apertured films are always desired, particularly those having improved fluid transport properties.
The present invention provides substrate having flocked fibers of superabsorbent polymer thereon, as well as an absorbent article comprising such as substrate.
The invention also provides an apertured film having flocked fibers of superabsorbent polymer thereon. The flocked fibers of superabsorbent polymer may be on the top surface or the underside surface of the apertured film, or on the sidewalls of the apertures themselves.